refactor(projects): build the projects list on the octokit SDK

Replace hand-rolled REST paging, GraphQL cursor loops and header plumbing with
octokit, which also brings request retry and rate-limit backoff. Introduces the
repo's first package.json, lockfile and ESLint flat config; the Hugo site build
itself still needs no Node step.

Output verified against the previous implementation: identical counts and rows
apart from live star drift on four upstream repos.

.github/workflows/update-projects.yml

@@ -29,6 +29,10 @@ jobs:
         uses: actions/setup-node@v6
         with:
           node-version: 24
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
 
       - name: Refresh projects list
         env: